CN118039311A

CN118039311A - Flat magnetic element

Info

Publication number: CN118039311A
Application number: CN202311504360.0A
Authority: CN
Inventors: 邱奕勋; 张溢盛; 赖建安; 朱家苇
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2022-11-14
Filing date: 2023-11-13
Publication date: 2024-05-14
Also published as: TW202420346A; EP4369365A1; TW202420723A; TW202427508A; EP4369366A1; TWM656161U; EP4369363A2; CN118041064A; US20240161967A1; US20240161969A1; TW202420345A; US20240161968A1; EP4369363A3; CN118039312A; EP4369364A1; US20240161966A1; US20240162833A1; CN118039313A; TW202429494A; EP4369586A1

Abstract

The invention provides a flat magnetic element which is configured on a circuit board of a resonant converter, wherein the resonant converter comprises a primary side circuit and a secondary side circuit, and the flat magnetic element comprises an inductance wire, an inductance iron core and a current transformer wire. The inductance trace is configured on the primary side circuit and formed on one layer of the circuit board to serve as a resonance inductance coupled with the primary side circuit. The inductance core comprises a core column, the core column penetrates through the through hole of the circuit board, and the inductance routing ring is wound around the through hole. The shunt wire is formed on the other layer board of the circuit board and is used as a shunt coil for coupling the resonance inductance. The shunt trace surrounds the perforation to form a common core structure of the common inductance core.

Description

Flat magnetic element

Technical Field

The present invention relates to a planar magnetic element, and more particularly, to a planar magnetic element integrated with a comparator.

Background

With the rapid development of the information industry, power supplies have played an indispensable role. The input voltage of the information and home appliances is divided into an ac voltage and a dc voltage, and the power supply may be generally divided into two levels. Typically the front stage is typically an AC/DC converter, a power factor corrector or a DC/DC converter, and the back stage is typically a resonant converter. The resonant converter is a DC-DC power converter, which has the advantages of high output power and high conversion efficiency compared with other converters because the primary side switch is turned on (turn on) and the secondary side rectifier switch is turned off (turn off). And a rectifier switch is adopted on the secondary side, so that the performance of high efficiency and high power density can be realized more easily.

The resonant converter generally includes magnetic elements such as a resonant inductor and a transformer, and the magnetic elements generally include a coil, a bobbin and an iron core. The coil is formed by winding copper wires on the winding frame for more than tens of circles, and then the iron core is used for sleeving the winding wires to form a closed magnetic circuit. Therefore, the resonant inductor and the transformer generally have the fatal disadvantage of huge volume, and cannot effectively reduce the volume of the resonant converter, so that the power supply has the problems of huge volume and poor power density.

In another aspect, fig. 1 is a block diagram of a conventional current transformer coupled resonant converter. The conventional current detection is to have a current comparator 5 (Current transformer, CT) in the primary path string, and the current comparator 5 includes a current comparator primary side coil 5A and a current comparator secondary side coil 5B. The current transformer 5 generally needs to wind the primary side coil 5A and the secondary side coil 5B of the current transformer around the core of the current transformer to perform current detection, so that a large space and a large safety distance are generally required to meet the design requirements. Therefore, the volume of the resonant converter cannot be effectively reduced, which results in the problems of huge volume of the power supply and poor power density.

Therefore, how to design a planar magnetic element to replace the conventional magnetic element in the resonant converter and integrate the current transformer coil in the planar magnetic element so as to greatly reduce the volume of the resonant converter is a big subject for the present inventor to study.

Disclosure of Invention

In order to solve the above-mentioned problems, the present disclosure provides a flat magnetic element to overcome the problems of the prior art. Therefore, the flat magnetic element is arranged on the circuit board of the resonant converter, the resonant converter comprises a primary side circuit and a secondary side circuit, and the flat magnetic element comprises an inductance wire, an inductance iron core and a current transformer wire. The inductance trace is configured on the primary side circuit and formed on one layer of the circuit board to serve as a resonance inductance coupled with the primary side circuit. The inductance core comprises a core column, the core column penetrates through the through hole of the circuit board, and the inductance routing ring is wound around the through hole. The shunt wire is formed on the other layer board of the circuit board and is used as a shunt coil for coupling the resonance inductance. The shunt wire surrounds the perforation to form a common core structure of the common inductance core.

In order to solve the above-mentioned problems, the present disclosure provides a flat magnetic element to overcome the problems of the prior art. Therefore, the flat magnetic element is arranged on the circuit board of the resonant converter, the resonant converter comprises a primary side circuit and a secondary side circuit, and the flat magnetic element comprises a primary side wire, a secondary side wire, an iron core and a current transformer wire. The primary side wiring is formed on one of the boards and serves as a primary side coil coupled to the primary side circuit. The secondary side trace is formed on another layer of the circuit board and serves as a secondary side coil coupled to the secondary side circuit. The iron core comprises a first iron core column and a second iron core column, the first iron core column and the second iron core column respectively penetrate through a first perforation and a second perforation of the circuit board, and the primary side wiring and the secondary side wiring are wound around the first perforation and the second perforation. The shunt trace is formed on another layer of the circuit board and serves as a shunt coil coupled to the secondary side coil. The comparator wire surrounds the first perforation or the second perforation to form a common iron core structure of the common iron core.

The main objective and effect of the present disclosure is that, since the resonant converter of the present disclosure uses the structure of the planar magnetic element and planarizes the current transformer coil to integrate the planar magnetic element, the effects of omitting the primary side coil of the current transformer and the current transformer core, reducing the contact impedance caused by the current transformer, increasing the efficiency and increasing the power density can be achieved.

For a further understanding of the technology, means, and efficacy of the present invention, reference should be made to the following detailed description of the invention and to the accompanying drawings, which are included to provide a further understanding of the invention, and to the features and aspects of the invention, however, are given by way of illustration and not limitation.

Drawings

FIG. 1 is a block diagram of a conventional current transformer coupled resonant converter;

FIG. 2A is a block diagram of a resonant converter of the present disclosure;

FIG. 2B is a schematic diagram of a circuit structure of the current transformer coil coupled to the secondary side coil of the present disclosure;

FIG. 3A is an exploded view of a three-dimensional circuit structure of a resonant converter of the present disclosure;

FIG. 3B is a schematic diagram of a resonant converter of the present disclosure;

FIGS. 4A-4L are schematic diagrams illustrating the routing of coils of the planar magnetic element of the present disclosure to various layers of a circuit board; and

Fig. 5A-5C are schematic diagrams illustrating additional embodiments of the routing of coils of the planar magnetic element of the present disclosure to layers of a circuit board.

Reference numerals illustrate:

100 … resonant converter

CB1 … circuit board

OUT_P1 … connecting terminal

PE … flat-plate magnetic element

C1 … iron core

C12 … first core limb

H1 … first perforation

C14 … second core limb

H2 … second perforation

C_L … inductance core

C_LC … iron core column

H3 … perforation

1A … Primary side Circuit

SA1_ M, SA1_N … switch bridge arm

Q1-Q4 … power switch

Lr … resonant inductor

Lc … inductor

Tl … inductance wiring

Cr … resonant capacitor

2A … transformer

22A … primary side coil

Tp1 … primary side wiring

24A … secondary side coil

24A-1 … first coil

24A-2 … second coil

Ts1 … secondary side wiring

Ts1_ … first wiring

Ts1_ … second wiring

3A … secondary side circuit

32 … Rectifying circuit

SR1, SR2 … rectifier switch

4A … controller

5 … Comparator

5A … ratio transformer primary side coil

5B … ratio transformer secondary side coil

52A, 52B … specific current transformer coil

Rs … detection resistor

Tca, tcb … specific current device wiring

Tcb1 … first comparator trace

Tcb2 … second current transformer trace

Via holes via …

200 … Pre-stage circuit

300 … Load

400 … Current detection circuit

V_DC … direct-current power supply

V_M … main power supply

Vc … cross-pressure

I1 … first current

I2 … second current

Ia … sense Current

Detailed Description

The technical content and detailed description of the present invention are as follows in conjunction with the accompanying drawings:

Please refer to fig. 2A, which is a block diagram of a resonant converter of the present disclosure, and in combination with fig. 1. The resonant converter 100 may be coupled to the pre-stage 200 and the load 300, and the pre-stage 200 may be a dc power supply such as an ac/dc converter, a pfc, a dc source, etc. The resonant converter 100 includes a primary side circuit 1A, at least one set of transformers 2A (shown as two sets in this embodiment), at least one set of secondary side circuits 3A (shown as one set in this embodiment), and a controller 4A, and the transformers 2A include a primary side coil 22A and a secondary side coil 24A. Taking fig. 1 as an example, the primary side circuit 1A is a full-bridge architecture. The primary side circuit 1A includes two sets of switch legs s1_ M, SA1_n and one set of resonant tanks (i.e. resonant inductor Lr and resonant capacitor Cr), and the switch legs s1_ M, SA1_n include two power switches (Q1 to Q4) connected in series respectively. The secondary side circuit 3A includes two sets of rectifying circuits 32, and the rectifying circuits 32 include two rectifying switches (SR 1, SR 2), respectively. The secondary side coils 24A of the two sets of transformers 2A respectively include a first coil 24A-1 and a second coil 24A-2, and the first coil 24A-1 and the second coil 24A-2 are center-tapped coils. The resonant converter 100 may control on/off of the rectification switches (SR 1, SR 2) by the controller 4A so that the first coil 24A-1 and the second coil 24A-2 are coupled to the primary side coil 22A, respectively.

In general, the controller 4A controls the switching bridge arms s1_ M, SA _n and the rectifying switches (SR 1, SR 2) of the rectifying circuit 32 to store/release energy from the resonant tank and the transformer 2A, so as to convert the direct current power v_dc received by the resonant converter 100 into the main power v_m through the energy storage/release of the resonant tank and the transformer 2A. Since only one of the rectifying switches SR1, SR2 is operated at the same time. Therefore, when the rectifying switch SR1 is turned on, the first coil 24A-1 and the rectifying switch SR1 form a current loop, and the first coil 24A-1 flows through the first current I1. When the rectifying switch SR2 is turned on, the second coil 24A-2 and the rectifying switch SR2 form a current loop, and the second coil 24A-2 flows through the second current I2. It should be noted that, in one embodiment, the circuit structures of the primary side circuit 1A and the secondary side circuit 3A are merely illustrative examples, and the primary side circuit 1A (such as, but not limited to, a half-bridge structure, a set of resonant tanks, etc.) and the secondary side circuit 3A (such as, but not limited to, a half-bridge rectifying circuit, a single set of rectifying circuits, etc.) that can constitute the structure of the resonant converter 100 are included in the scope of the present embodiment. In addition, in an embodiment, the number of the transformers 2A may be 2 as shown in fig. 1, but not limited thereto, and may be implemented by more than one group of transformers 2A. That is, when the number of transformers 2A is 1, the resonant converter 100 includes only one set of the primary side coil 22A, the first coil 24A-1, and the second coil 24A-2, and so on.

Referring back to fig. 2A, the resonant converter 100 of the present disclosure also includes a shunt coil (52A, 52B). Compared to the prior art current transformer 5 of fig. 1 comprising a primary side transformer coil 5A and a secondary side transformer coil 5B, the present disclosure does not have a primary side transformer coil 5A because the primary side transformer coil 5A is integrated in the resonant inductance Lr and the secondary side coil 24A. The current comparator coils (52A, 52B) serve as the current comparator secondary side coil 5B for sensing the current flowing through the resonant inductance Lr and the secondary side coil 24A. In another aspect, the comparator coils (52A, 52B) of FIG. 2A may be coupled to, for example, but not limited to, a current detection circuit (not shown). The current detection circuit (not shown) can correspondingly generate a voltage signal according to the current sensed by the comparator coils (52A, 52B) to provide the voltage signal to the controller 4A, so that the controller 4A can know the magnitude of the current flowing through the resonant inductor Lr and the transformer 2A through the calculation of the voltage signal.

Please refer to fig. 2B, which is a schematic diagram of a circuit structure of the current transformer coil coupled to the secondary side coil of the present disclosure, and fig. 2A. One end of the shunt coil 52B is coupled to one end of the first coil 24A-1 or the second coil 24A-2, and the other end of the shunt coil 52B is coupled to the detection resistor Rs. Thus, the comparator coil 52B and the sense resistor Rs are connected in parallel to the first coil 24A-1 or the second coil 24A-2. For convenience of explanation, the secondary side currents flowing through the rectifier switches SR1 and SR2 are herein distinguished as the first current I1 and the second current I2, respectively. When the current comparator coil 52B is coupled to the first coil 24A-1 and the first current I1 flows through the first coil 24A-1, the current comparator coil 52B senses the sense current Ia. The sense current Ia flows through the sense resistor Rs to generate a voltage across the sense resistor Rs, and a current detection circuit (not shown) coupled to the rear end generates a voltage signal according to the voltage across the sense resistor Rs. Further, since the voltages at the two ends of the first coil 24A-1 are equal to the voltage at the two ends of the comparator coil 52B and the detection resistor Rs, and the first current I1 has a corresponding relationship with the sensing current Ia, the controller 4A can know the magnitude of the first current I1 through the calculation of the crossover voltage Vc. In another aspect, the operation of coupling the comparator coil 52B to the second coil 24A-2 is similar to that of the first coil 24A-1, and will not be described again. Since the shunt coil 52B is used only for sensing the shunt current Ia, its current value is not preferably excessively large. Therefore, the resistance of the detection resistor Rs is not too small, and a resistor having a resistance of, for example, but not limited to, 10k or more is preferable.

Please refer to fig. 3A for an exploded view of a three-dimensional circuit structure of the resonant converter of the present disclosure, fig. 3B for a combined view of a three-dimensional circuit structure of the resonant converter of the present disclosure, and fig. 2A for a double fit. The resonant converter 100 is disposed on the circuit board CB1, and the switch arm SA1_ M, SA1 _1_n and the controller 4A are disposed at the positions shown in fig. 3A. Wherein the resonant inductance Lr forms a planar magnetic element PE with the (at least one) transformer 2A. Specifically, the inductance coil Lc of the resonant inductor Lr and the primary side coil 22A and the secondary side coil 24A of the transformer 2A are both planar structures and formed on the circuit board CB 1. The core C1 forms (at least one) transformer 2A by being directly sleeved on the primary side coil 22A and the secondary side coil 24A of the circuit board CB1, and the inductor core c_l forms the resonant inductance Lr by being directly sleeved on the inductor coil Lc of the circuit board CB 1.

Therefore, the resonant converter 100 structure of the present disclosure mainly forms the inductance coil Lc of the resonant inductor Lr and the primary side coil 22A and the secondary side coil 24A of the transformer 2A on the circuit board CB1, so that the planar magnetic element PE can be planarized (planar), thereby greatly improving the space utilization of the resonant converter 100 and achieving the high power density requirement. In addition, the resonant converter 100 also has the characteristic of small size due to the use of the flat-plate magnetic element PE, and the operating frequency of the resonant converter 100 can be greatly increased, so that the power switches of the switch bridge arm SA1_ M, SA1_n and the rectifying circuit 32 can use the third generation semiconductor element such as the wide energy gap (WBG) as the main power switch, which makes the resonant converter 100 have the advantages of higher efficiency, significantly reduced power switch size, lighter weight, improved heat dissipation performance and the like.

In another aspect, the current comparator coils (52A, 52B) of the present disclosure are also of a planar (planar) structure and are formed on the circuit board CB 1. The current comparator coil 52A is formed near the inductance coil Lc so as to be able to induce a current flowing through the inductance coil Lc by coupling, and the current comparator 52A is formed to sense the primary side current by reusing the common core structure that shares the inductance core c_l with the inductance coil Lc. Similarly, the current comparator coil 52B is formed near the secondary side coil 24A so as to be able to sense the current flowing through the secondary side coil 24A by coupling, and the current comparator coil 52B is formed by reusing the common core structure of the common core C1 with the secondary side coil 24A to sense the secondary side current. Therefore, by the common-core structure, the circuit volume of the resonant converter 100 can be greatly reduced, and the space utilization rate of the resonant converter 100 can be greatly improved to meet the requirement of high power density.

Please refer to fig. 4A-4L, which are schematic diagrams illustrating the routing of the coils of the planar magnetic element of the present disclosure on each layer of the circuit board, in combination with fig. 2A-3B. The circuit board CB1 is a multi-layer board (here, for example, but not limited to, 12-layer board), fig. 4A is a top layer board, and fig. 4L is a bottom layer board. The inductor track Tl serves as an inductor Lc, and the primary track Tp1 serves as a primary coil 22A. The plurality of inductor traces Tl and the plurality of primary-side traces Tp1 are formed on the laminate (i.e., the primary laminate) of fig. 4B, 4E, 4H, and 4K, respectively. Specifically, the inductor traces Tl may be connected in series as the inductor Lc through communication (e.g., using the via) of each primary layer board. Likewise, the primary side traces Tp1 may be connected in series with the primary side traces Tp1 as primary side coils 22A coupled to the primary side circuit 1A by communication (e.g., using vias via) of the respective primary boards, respectively.

The plurality of secondary side wires Ts1 are formed as secondary side coils 24A in the laminate (i.e., referred to as secondary laminate) of fig. 4A, 4C to 4D, 4F to 4G, 4I to 4J, and 4L. Specifically, the secondary side wires Ts1 may be connected in series (e.g., using via) to the secondary side wires Ts1 through the communication of the secondary boards, respectively, so as to serve as the secondary side coil 24A coupled to the secondary side circuit 3A. Referring to fig. 3A to 3B, the core C1 includes a first core limb C12 and a second core limb C14. The first core leg C12 penetrates through the first through hole H1 of the circuit board CB1, and the second core leg C14 penetrates through the second through hole H2 of the circuit board CB 1. The primary side wires Tp1 of each primary layer board encircle the first through hole H1 and the second through hole H2, and the secondary side wires Ts1 of each secondary layer board encircle the first through hole H1 and the second through hole H2, so that the iron core C1 is sleeved on the primary side wires Tp1 and the secondary side wires Ts1, and then a closed magnetic circuit can be formed to form the transformer 2A. Similarly, the inductor core c_l includes core legs c_lc. The core column c_lc penetrates through the through hole H3 of the circuit board CB1, and the inductance trace Tl of each primary layer board surrounds the through hole H3, so that the inductance core c_l is sleeved on the inductance trace Tl, and a closed magnetic circuit can be formed to form the resonant inductor Lr. It should be noted that, in one embodiment, the material of the traces formed by each laminate may be copper foil, but it is not excluded that other metal foils (such as but not limited to gold, silver, etc.) that are easy to conduct may be used.

In fig. 4B, 4E, 4H, and 4K, the primary side trace Tp1 surrounds the first through hole H1 in a first direction D1 (clockwise/counterclockwise), and surrounds the second through hole H2 in a second direction D2 (counterclockwise/clockwise) opposite to the first direction D1, so as to form an ++shaped trace. That is, when the primary trace Tp1 surrounds the first through hole H1 in a clockwise direction, it surrounds the second through hole H2 in a counterclockwise direction. Conversely, when the primary trace Tp1 surrounds the first through hole H1 in the counterclockwise direction, it surrounds the second through hole H2 in the clockwise direction. In the adjacent primary laminates (for example, but not limited to, fig. 4B and 4E), the surrounding direction of the primary trace Tp1 is the same (referred to as the flowing direction of the primary current). For example, in fig. 4B, taking a situation in which the first rectifying switch SR1 is turned on as an example, the primary-side trace Tp1 starts from the first through hole H1 in a clockwise direction (the first direction D1) and approaches the second through hole H2 in a counterclockwise direction (the second direction D2). The current paths adjacent to the primary side trace Tp1 (fig. 4E) are opposite, and the primary side trace Tp1 approaches the first through hole H1 in a clockwise direction (first direction D1) and starts from the second through hole H2 in a counterclockwise direction (second direction D2). And so on, no further description is given.

It should be noted that, in one embodiment, the primary side trace Tp1 shown in fig. 4B, 4E, 4H, and 4K forms two groups of primary side coils 22A as shown in fig. 3A, but it is understood that, similarly, depending on the circuit configuration of the resonant converter 100, the primary side trace Tp1 may form more than one group of primary side coils 22A. The number of the groups can be increased according to the number of layers of the first circuit board CB1 and the number of turns of the primary side trace Tp1, which will not be described herein.

In fig. 4B, when the second rectifying switch SR2 is turned on, the primary-side trace Tp1 starts from the first through hole H1 in the counterclockwise direction (the first direction D1) and approaches the second through hole H2 in the clockwise direction (the second direction D2). And so on, no further description is given. Therefore, the first direction D1 and the second direction D2 refer to the current direction surrounding the first through hole H1 and the second through hole H2 as two different current directions, and are not limited by the clockwise direction or the counterclockwise direction. Therefore, the primary-side trace Tp1 surrounds at least two circles around the first through hole H1 and the second through hole H2, respectively, and forms a pattern similar to ≡infinity, which is called ≡infinity.

In another aspect, the primary side trace Tp1 of the present disclosure further integrates the inductor trace Tl, and the inductor trace Tl surrounds the through hole H3. Further, as shown in fig. 1, the resonant inductance Lr is a circuit element different from the transformer 2A, and in fact, the two may be separately configured (i.e., may include other circuit elements such as, but not limited to, a resonant capacitor Cr therebetween). However, the two circuit elements are similar in category and have a coil structure, so the present disclosure is to integrate the inductance coil Lc of the resonant inductor Lr with the primary side coil 22A to form the planar magnetic element PE in a preferred embodiment, but the present disclosure is not limited thereto. That is, the metal foil of the inductor trace Tl of the present disclosure is directly connected to the metal foil of the primary side trace Tp1 to form a common trace structure. Therefore, the whole metal foil of fig. 4B, 4E, 4H, and 4K is an integrally formed structure, and a part of the integrally formed metal foil belongs to the inductance trace Tl and the other part thereof belongs to the primary side trace Tp1.

On the other hand, in fig. 4B, 4E, 4H, and 4K, the inductance trace Tl and the metal foil of the primary side trace Tp1 are formed in the same layer and are integrally formed. However, the inductor track Tl and the primary track Tp1 may be respectively formed in different layers and coupled by the via. Therefore, as long as the metal foil of the inductance trace Tl can be coupled to the primary side trace Tp1 by a coupling manner (for example, but not limited to, via, or other circuit elements including the resonance capacitor Cr therebetween) to form the same path. Therefore, the metal foil of the inductor track Tl and the primary track Tp1 is integrally formed as shown in fig. 4B, 4E, 4H, and 4K. In fact, however, the metal foils of the inductor track Tl and the primary track Tp1 may be configured separately (i.e., the inductor track Tl of fig. 4B, 4E, 4H, 4K is disconnected from the metal foil of the primary track Tp 1) and coupled by a via or other circuit element that may be connected in series on this path. It should be noted that, in one embodiment, the primary side trace Tp1 shown in fig. 4B, 4E, 4H, and 4K forms two groups of primary side coils 22A as shown in fig. 2A, but it is understood that, similarly, depending on the circuit configuration of the resonant converter 100, the primary side trace Tp1 may form more than one group of primary side coils 22A. The number of the groups can be increased according to the number of layers of the first circuit board CB1 and the number of turns of the first primary side trace Tp1, which will not be described herein.

Further, in the structure of the secondary side trace Ts1 in fig. 4A, 4C to 4D, 4F to 4G, 4I to 4J, and 4L, the secondary side trace Ts1 forms an m-shaped trace with the first through hole H1 and the second through hole H2. The current flowing through the secondary side trace Ts1 may flow from the center point of the m-word to the two ends, or may flow from the two ends of the m-word to the center point (according to the operation of the rectifier switches (SR 1, SR 2), as will be further described later). A plurality of vias via holes via may be included at the bottom of m, and the via holes may be filled with conductive material, so that the secondary side traces Ts1 of the secondary board of fig. 4A, 4C-4D, 4F-4G, 4I-4J, and 4L may be electrically connected through the via holes.

Specifically, since the secondary side coil 24A has a center-tapped coil structure, the secondary side wire Ts1 includes at least one first wire ts1_1 (1 each shown in fig. 4A, 4F, and 4I to 4J) and at least one second wire ts1_2 (1 each shown in fig. 4C to 4D, 4G, and 4L). Therefore, the number of layers of the multilayer circuit board CB1 may be at least three, so that the top layer, the middle layer and the bottom layer may respectively form a first trace ts1_1, a second trace ts1_2 and an integrated primary side trace Tp1 and an inductance trace Tl, and when the number of layers increases, the number of the first trace ts1_1, the second trace ts1_2, the primary side trace Tp1 and the inductance trace Tl may be selectively increased (based on circuit requirements). The first wires ts1_1 of the secondary boards of fig. 4A, 4F, 4I-4J may form two groups of first coils 24A-1 through connection of the via hole via, and the second wires ts1_2 of the secondary boards of fig. 4C-4D, 4G, 4L may form two groups of second coils 24A-2 through connection of the via hole via (as shown in fig. 2A). Similarly, although the secondary side trace Ts1 shown in fig. 4A, 4C-4D, 4F-4G, 4I-4J, and 4L may form two sets of secondary side coils 24A as shown in fig. 1, it is understood that the secondary side trace Ts1 may form more than one set of secondary side coils 24A according to the circuit configuration of the resonant converter 100. The number of the groups can be increased according to the number of layers of the circuit board CB1 and the number of turns of the secondary side trace Ts1, which will not be described herein.

The first trace ts1_1 surrounds the first through hole H1 and the second through hole H2 to form an m-word trace. Similarly, the second trace ts1_2 also surrounds the first through hole H1 and the second through hole H2 to form an m-word trace. The difference is that the current direction of the first trace ts1_1 in fig. 4A, 4F, and 4I to 4J flows from the two ends of the m-word to the first power output terminal out_p1 of the circuit board CB1 toward the center point. On the contrary, the current direction of the second trace ts1_2 in fig. 4C to 4D, 4G and 4L is exactly opposite to that of the first trace ts1_1, and the current flows from the center point of the m-word to the first power output terminal out_p1 of the circuit board CB 1.

In fig. 4D, the shunt wires (Tca, tcb) are shown, and serve as shunt coils (52A, 52B), respectively. The current transformer wire Tca and the inductance wire Tl are configured on different layers, and the current transformer wire Tca surrounds the through hole H to couple the inductance wires Tl of different layers. Therefore, the circuit board CB1 forms a closed magnetic circuit after the inductor core c_l is sleeved on the inductor trace Tl and the current comparator trace Tca, thereby forming a resonant inductor Lr and a current comparator sharing an iron core structure with the resonant inductor Lr. The current transformer wire Tcb and the second wire ts1_2 are disposed on the same layer, and the current transformer wire Tcb and the second wire ts1_2 of the secondary side wire Ts1 have a concentric circle structure. In another aspect, the shunt trace Tcb may be disposed on the same layer as the first trace ts1_1, and the shunt trace Tcb and the second trace ts1_2 of the secondary side trace Ts1 may have a concentric structure.

In fig. 4D, the shunt trace Tcb surrounds the first through hole H1 to couple to the second trace ts1_2 of the same layer. Therefore, the circuit board CB1 can form a closed magnetic circuit after the core C1 is fitted over the primary side trace Tp1, the secondary side trace Ts1, and the shunt trace Tcb, thereby forming the transformer 2A and the shunt having a common core structure with the transformer 2A. Assuming that the current transformer Tcb and the first wire ts1_1 are disposed on the same layer, when the rectification switch SR1 is turned on, the current transformer Tcb can induce the first current I1 flowing through the first wire ts1_1. Conversely, it is assumed that the current comparator wire Tcb and the second wire ts1_2 are disposed on the same layer, and when the rectification switch SR2 is turned on, the current comparator wire Tcb can induce the second current I2 flowing through the second wire ts1_2. Since the rectifying switch SR1 and the rectifying switch SR2 (or diode) are designed to be complementary conductive (forward bias), when the rectifying switch SR1 is turned on, the rectifying switch SR2 is turned off, and vice versa. The position of the shunt trace Tcb is closer to the first through hole H1 than the second trace ts1_2 of the secondary side trace Ts1, so that the core C1 is sleeved on the secondary side trace Ts1 and the shunt trace Tcb, and then a closed magnetic circuit can be formed to form the transformer 2A and the shunt having a common core structure with the transformer 2A.

The specific current path Tca surrounding the through hole H has a first area, and the inductance path Tl surrounding the through hole H has a second area. Since the current comparator is mainly used for inducing the magnitude of the current flowing through the resonant inductor Lr, the current flowing through the current comparator coil 52A is not too large, and therefore the first area must be smaller than the second area, and the area difference is preferably 1/5 to 1/10. Similarly, the comparator wire Tcb surrounding the first through hole H1 has a third area, and the secondary side wire Ts1 surrounding the first through hole H1 has a fourth area, which is also necessarily smaller than the fourth area, and the area difference is preferably 1/5 to 1/10.

Please refer to fig. 5A-5C, which are schematic diagrams illustrating an additional embodiment of the coil of the planar magnetic element of the present disclosure in the wiring of the layers of the circuit board, and further refer to fig. 2A-4L. The wiring structures in fig. 5A to 5C are only simple wiring diagrams, and thus only the wirings of the main elements are shown, and the detailed structures thereof can be easily deduced from the structures in fig. 4A to 4L. In fig. 5A, the shunt trace Tca and the inductor trace Tl are disposed on the same layer, and the shunt trace Tca is disposed closer to the through hole H than the inductor trace Tl. Wherein the comparator trace Tca may be coupled to a current detection circuit (not shown) by, for example, but not limited to, a via. In fig. 5B, the shunt trace Tcb and the first trace ts1_1 are arranged on the same layer, and the shunt trace Tcb and the first trace ts1_1 of the secondary side trace Ts1 have a concentric circle structure. The comparator trace Tcb surrounds the second through hole H2 to couple the first trace ts1_1, which surrounds the second through hole H2, in the same laminate. Thus, similar to fig. 4D, when the rectifying switch SR1 is turned on, the comparator track Tcb can induce a first current I1 flowing through the first track ts1_1. The position of the shunt trace Tcb is closer to the second through hole H2 than the first trace ts1_1 of the secondary side trace Ts1, so that the core C1 is sleeved on the secondary side trace Ts1 and the shunt trace Tcb, and then a closed magnetic circuit can be formed to form the transformer 2A and the shunt having a common core structure with the transformer 2A.

In fig. 5C, the comparator wiring Tcb includes a first comparator wiring Tcb1 and a second comparator wiring Tcb2, and the second comparator wiring Tcb2 and the first comparator wiring Tcb1 are arranged on the same layer. The first comparator wire Tcb1 and the second comparator wire Tcb2 (similar to the comparator wire Tca of fig. 4D) are independently configured on the layer, but the first comparator wire Tcb1 and the second comparator wire Tcb2 do not exclude that one of the first wire ts1_1 and the second wire ts1_2 may be configured on the same layer, as long as the second comparator wire Tcb2 and the first comparator wire Tcb1 are configured on the same layer. The first comparator wire Tcb1 surrounds the first through hole H1, and the second comparator wire Tcb2 surrounds the second through hole H2 to couple the first wire ts1_1 and the second wire ts1_2 of different layers. Since the rectifying switch SR1 and the rectifying switch SR2 (or diodes) are designed to be complementary conductive (forward bias), when the rectifying switch SR1 is operated, the first comparator wire Tcb1 and the second comparator wire Tcb2 can induce the first wire ts1_1 to flow therethrough, and when the rectifying switch SR2 is operated, the first comparator wire Tcb1 and the second comparator wire Tcb2 can induce the second current I2 flowing through the second wire ts1_2 therethrough. It should be noted that, in an embodiment, the configuration features of fig. 4A to 5C may be applied alternately, and will not be described herein.

Since the current transformer coils (52A, 52B) of the present disclosure have planar current transformer traces Tca, tcb, and are integrated into the inductance trace Tl and the secondary side trace Ts1, respectively, to form the structure of the planar magnetic element PE. In this way, current detection can be achieved by using the turns ratio of the current transformer tracks Tca, tcb to the inductor track Tl and the secondary side track Ts1, respectively. Therefore, the resonant converter 100 of the present disclosure can omit the primary side coil 5A and the core of the current transformer 5, reduce the contact resistance caused by the current transformer, increase the efficiency and increase the power density. In addition, the use of the integrated flat-type magnetic element PE can increase the space utilization of the resonant converter 100 and reduce the labor force for assembly. In addition, the primary side coil 22A and the secondary side coil 24A of the transformer 2A can be distributed effectively, thereby reducing ac eddy current loss and improving efficiency.

The above detailed description and drawings are only illustrative of the preferred embodiments of the present invention, and the present invention is not limited thereto, but rather, the scope of the present invention is defined by the appended claims, and all embodiments falling within the spirit and scope of the claimed invention and similar changes thereto are intended to be included in the scope of the present invention, and any changes or modifications easily contemplated by those skilled in the art within the present invention are intended to be covered by the following claims.

Claims

1. A planar magnetic element disposed on a circuit board of a resonant converter, the resonant converter including a primary side circuit and a secondary side circuit, the planar magnetic element comprising:

An inductance trace configured on the primary side circuit and formed on one of the circuit boards as a resonance inductance coupled to the primary side circuit;

the inductance iron core comprises an iron core column, the iron core column penetrates through the perforation of the circuit board, and the inductance routing ring is wound on the perforation; and

A shunt wire formed on the circuit board and serving as a shunt coil for coupling the resonant inductor;

the shunt wire surrounds the through hole to form a common iron core structure sharing the inductance iron core.

2. The planar magnetic element of claim 1 wherein the shunt trace surrounding the via has a first area and the inductor trace surrounding the via has a second area, the first area being smaller than the second area.

3. The planar magnetic element of claim 1 wherein the shunt trace and the inductor trace are disposed on the same layer and the shunt trace is disposed closer to the aperture than the inductor trace.

4. The planar magnetic element of claim 1 wherein the planar magnetic element further comprises:

A primary side trace formed on one of the circuit boards and serving as a primary side coil coupled to the primary side circuit;

The primary side wire surrounds a first through hole in a first direction and surrounds a second through hole in a second direction to form an ++shaped wire.

5. The planar magnetic element of claim 4 wherein the metal foil of the inductive trace is coupled to the metal foil of the primary side trace.

6. The planar magnetic element of claim 5 wherein the metal foil of the inductive trace is of unitary construction with the metal foil of the primary side trace.

7. A planar magnetic element disposed on a circuit board of a resonant converter, the resonant converter including a primary side circuit and a secondary side circuit, the planar magnetic element comprising:

A secondary side wiring formed on the other layer board of the circuit board and serving as a secondary side coil coupled with the secondary side circuit;

The iron core comprises a first iron core column and a second iron core column, the first iron core column and the second iron core column respectively penetrate through a first perforation and a second perforation of the circuit board, and the primary side wiring and the secondary side wiring are wound around the first perforation and the second perforation; and

A current transformer wire formed on the circuit board and serving as a current transformer coil coupled to the secondary side coil;

The comparator wire is wound around the first perforation or the second perforation to form a common iron core structure sharing the iron core.

8. The planar magnetic element of claim 7 wherein the shunt trace surrounding the first or second through-holes has a third area and the secondary side trace surrounding the first or second through-holes has a fourth area, the third area being smaller than the fourth area.

9. The planar magnetic element of claim 7 wherein the shunt trace and the secondary side trace are disposed on the same layer and the shunt trace is disposed closer to the first aperture or the second aperture than the secondary side trace.

10. The planar magnetic element of claim 7 wherein the circuit board is a multi-layer board and the secondary side coil is a center tap coil structure to form at least one first trace and at least one second trace on the circuit board; the at least one first wiring is wound around the first through hole and the second through hole to form an m-shaped wiring, and the at least one second wiring is wound around the first through hole and the second through hole to form the m-shaped wiring.

11. The planar magnetic element of claim 10 wherein the shunt trace is looped around the first aperture to couple the at least one first trace and the at least one second trace.

12. The planar magnetic element of claim 10 wherein the shunt trace is routed around the second aperture to couple the at least one first trace and the at least one second trace.

13. The planar magnetic element of claim 10 wherein the shunt trace comprises:

a first comparator trace surrounding the first perforation; and

A second comparator wire which is arranged on the same layer with the first comparator wire and is wound around the second perforation;

The first comparator wire is coupled around the at least one first wire and the at least one second wire of the first through hole, and the second comparator wire is coupled around the at least one first wire and the at least one second wire of the second through hole.

14. The planar magnetic element of claim 7 wherein the primary-side trace is looped around the first via in a first direction and around the second via in a second direction to form an +..

15. The planar magnetic component of claim 7 wherein the metal foil of an inductor trace is coupled to the metal foil of the primary side trace.

16. The planar magnetic element of claim 15 wherein the metal foil of the inductive trace is of unitary construction with the metal foil of the primary side trace.